The spinal column includes, among other structures, the bony vertebrae which surround the spinal cord, and the intervertebral discs. In a healthy spine, the discs maintain separation between the vertebrae, promote fluid circulation throughout the spine, and provide a cushioning effect between the bony vertebral structures. A variety of conditions can affect both the vertebrae and intervertebral discs.
Due to the elastic nature of an intervertebral disc, the disc is subject to injury if the disc becomes overstressed, for example, by trauma to the spine, excess body weight, improper mechanical movements and the like. Intervertebral disc injuries and other abnormalities result in serious back pain and physical disability and are often chronic and difficult to treat. Such abnormalities include, but are not limited to, localized tears or fissures in the disc annulus, localized disc herniations with contained or escaped nuclear extrusions, and circumferential bulging discs. Discs also experience degeneration over time which can accelerate these problems.
One of the common disc problems that occur when the entire disc bulges circumferentially about the annulus rather than in specific, isolated locations. This may occur for example, when over time, the disc weakens, bulges, and takes on a “roll” shape. The joint may become unstable and one vertebrae may eventually settle on top of another. This problem typically continues to escalate as the body ages, and accounts for shortened stature in old age. Osteophytes may form on the outer surface of the disc and further encroach upon the spinal canal and nerve foramina. This condition is called spondylosis.
Traditional non-surgical treatments of disc degeneration and abnormalities include bed rest, pain and muscle relaxant medication, physical therapy or steroid injection. Such therapies are directed primarily at pain relief and potentially delaying further disc degeneration. Eventually, most non surgical treatments fail In many cases surgical alternatives, often spinal fusion, may be the only option. Spinal fusion methods are aimed at causing the vertebrae above and below the injured disc to grow solidly together forming a single piece of bone. This procedure is carried out with or without discectomy (surgical removal of the disc). Another procedure, endoscopic discectomy, involves removing tissue from the disc percutaneously in order to reduce the volume of the disc, thereby reducing impingement of the surface of the disc on nearby nerves.